1. Field of the Invention
The present invention relates to a pull out assembly for a pullout tall cupboard and including a plurality of U-shaped rails displaceable relative to each other and formed of a sheet-metal strip material, with at least one rail having freely rotatable running and/or support rollers, with one of the rails being secured to a cupboard unit and another rail being secured to a bottom side of the pullout tall cupboard, and with the rail secured to the cupboard unit having a width larger than that of the rail secured to the pullout cupboard.
2. Description of the Prior Art
A pullout assembly for a tall cupboard is disclosed in Austrian Patent NO. 285,099. This assembly includes two C-shaped rails arranged one above the other, with the open sides of both rail facing each other. The height of this assembly is equal to the sum of both rails with the vertical spacing between the two rails being predetermined in advance. In this assembly, the diameter of the running rollers corresponds to the height of the rails. These rollers cannot be made sufficiently small, as they should carry an increased load. This pullout assembly is formed as a differential drawer. The running rollers are provided on rail located between the two C-shaped rails facing each other.
Another type of pullout assembly for a tall cupboard is disclosed in German Publication DE-OS 42 24 281. It includes a carcass rail formed of two identical U-shaped rails having their base webs spaced from each other and extending parallel to the middle or central plane of the cupboard pull-out, and a extendable or displaceable U-shaped rail which is connected with the cupboard, overlaps the carcass rail, is supported on the carcass rail by rollers, and has an incoming inclination. At that, a telescopic rail is arranged in a channel formed between the base webs of the rails forming the carcass rail. The telescopic rail has sidewise projecting upper and lower legs. The telescopic rail is supported on the carcass rail by rollers which engage the legs. At its outer end, the telescopic rail has rollers which cooperate with the incoming inclination of the extendable rail for supporting the same. At least one driver member is provided between the extendable and telescopic rails which provides for limited connections of the rails along a portion of the withdrawl and/or retracted stroke. This pullout assembly is very expensive. The advantage of the pullout assembly described in this German publication in comparison with that of the Austrian Patent NO. 285,099 consists in that it has a relatively small height.
There exist also pullout assemblies for tall cupboards built on so-called differentiated principle, which are designated for a permanent market. This assembly includes a U-shaped stationary rail securable to a furniture unit, an intermediate differential rail provided with running and support rollers, and another rail fixedly securable to an underside of a cupboard and the horizontal flanges of which are supported by rollers of the differential rail. The height of such differential pullout assembly can be very large. Therefore, the running rollers should have a relatively small diameter because in this type of a pullout assembly the running rollers should be arranged immediately one above the other. With these differential pullout assemblies, for complete withdrawal from the unit, the load should be somewhat lifted, because in the differential pullout assemblies, the running rollers are supported with some backlash. This adversely affects the serviceability of such assemblies, as these assemblies are sometimes used for tall cupboard carrying rather heavy loads.
U.S. Pat. No. 5,417,490 describes a pullout slide assembly for a tall cupboard formed of three rails. The rail, which is fixedly attached to a cupboard unit, has a U-shaped cross-section with inwardly directed flanges. The rail, which is attached to the pullout element, has an I-shaped cross-section and is formed of two profile members the upper horizontal flange of which is noticeably wider than the lower flange. The intermediate rail has a U-shaped cross-section having its upper flanges extending outwardly. The extendable I-shaped rail does not carry any support and running rollers. Rather, it is carried by support and running rollers provided on the intermediate rail. In this assembly, the intermediate rail is supported by rollers of the stationary rail which engage the outwardly extending flanges.
Finally, U.S. Pat. No. 3,450,446 discloses a drawer guide which is formed of drawn of rolled rails which have no support or running rollers but are provided only with rolling bodies mounted in a cage. Because of high costs associated with manufacturing of such assemblies, they did not find practical application.
Accordingly, an object of the present invention is to provide a pullout slide assembly for tall cupboards having a smallest height possible and convenient in exploitation.
Another object of the present invention is to provide a pullout slide assembly which can expand on the basis of a building block principle to achieve a maximum possible pullout length.